bluetooth: bluesleep: call free_irq during driver unload only

Signed-off-by: Varun Wadekar <vwadekar@nvidia.com>
Reviewed-on: http://git-master/r/67654
Reviewed-by: Rakesh Goyal <rgoyal@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User

Change-Id: Iabad9617752af43c7184d0335177c60fba6bd715